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Plasticity Induced by Shock Waves in Nonequilibrium Molecular-Dynamics Simulations
Brad Lee Holian,Peter S. Lomdahl +1 more
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In this article, nonequilibrium molecular-dynamics simulations of shock waves in three-dimensional 10-million atom face-centered cubic crystals with cross-sectional dimensions of 100 by 100 unit cells were presented.Abstract:
Nonequilibrium molecular-dynamics simulations of shock waves in three-dimensional 10-million atom face-centered cubic crystals with cross-sectional dimensions of 100 by 100 unit cells show that the system slips along all of the available {111} slip planes, in different places along the nonplanar shock front. Comparison of these simulations with earlier ones on a smaller scale not only eliminates the possibility that the observed slippage is an artifact of transverse periodic boundary conditions, but also reveals the richness of the nanostructure left behind. By introducing a piston face that is no longer perfectly flat, mimicking a line or surface inhomogeneity in the unshocked material, it is shown that for weaker shock waves (below the perfect-crystal yield strength), stacking faults can be nucleated by preexisting extended defects.read more
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Orientation-dependent responses of tungsten single crystal under shock compression via molecular dynamics simulations
TL;DR: In this paper, the orientation-dependent mechanical responses of shock loading on tungsten single crystal are investigated via molecular dynamics simulations via linear fitting our us-up data, which compare relatively well with the available experimental results.
Journal ArticleDOI
Shock relaxation by a strain induced martensitic phase transformation
TL;DR: In this article, a shuffle-type martensitic transformation was used to relax a uniaxial shock loaded state by slip or twinning, and a model was developed for relaxation by a martensite transformation for the case of copper shocked in a 〈110〉 direction.
Journal ArticleDOI
Deformation of metals under dynamic loading: Characterization via atomic-scale orientation mapping
TL;DR: In this paper, the orientation matrix representing the orientation of a crystallite consisting of a central atom and its nearest neighbors, and corresponding Euler angles, are calculated, which are used for orientation analysis and visualization.
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Molecular dynamics simulation of plastic effects upon spalling
TL;DR: In this paper, the effect of lattice defects in a material on the propagation of a shock wave and the process of spalling is studied using a model of imperfect particle packing with defects (vacancies).
Journal ArticleDOI
First principles electronic structure calculation and simulation of the evolution of radiation defects in plutonium by the density functional theory and the molecular dynamics approach
TL;DR: In this paper, a review is devoted to the description of fundamental properties of Pu based on ab initio and classical molecular-dynamics microscopic theories which could be linked to each other.
References
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Journal ArticleDOI
Shock-wave structure via nonequilibrium molecular dynamics and Navier-Stokes continuum mechanics
TL;DR: In this article, a strong steady dense-fluid shock wave is simulated with 4800-atom nonequilibrium molecular dynamics, and the resulting density, stress, energy, and temperature profiles are compared with corresponding macroscopic profiles derived from Navier-Stokes continuum mechanics.
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Fracture simulations using large-scale molecular dynamics
Brad Lee Holian,Ramon Ravelo +1 more
TL;DR: It is found that the can suppress ductile behavior by including viscous damping in the equations of motion, thereby demonstrating a transition to brittle crack propagation as static, zero-strain-rate conditions are approached.
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Dislocation Dynamics and Dynamic Yielding
TL;DR: In this article, the dislocation dynamics of Gilman and Johnston were applied to the problem of elastic elastic flow in Armco iron at very high strain rates, and the initial density of dislocation lines, N0, was found to be 2.0×108 cm−2.
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Large-Scale Molecular Dynamics Simulations of Three-Dimensional Ductile Failure
TL;DR: In this paper, the authors performed massively parallel 3D molecular dynamics simulations with up to 35 million atoms to investigate ductile failure, obtaining mechanistic information at the atomistic level inaccessible to experiment.
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A mechanism for dislocation generation in shock-wave deformation
TL;DR: Hornbogen as discussed by the authors proposed a modification to Smith's (9) model, based on the fact that shockloaded iron (between 7 and II GPa) presents a substructure characterized by straight screw dislocations.